CentOS - Jul 2011 - How to test for '.' in a script

I am trying to check for a single period '.' in a shell variable.

$ I=.
$ echo $I
.
$ if [[ "$I" -eq '.' ]]; then echo true; fi
-bash: [[: .: syntax error: operand expected (error token is ".")

All other variants of this construct, with and without escape
characters, single and double quote combinations, that I can think
of all give exactly the same error.

How does one check to see for this in a bash script?


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> $ if [[ "$I" -eq '.' ]]; then echo true; fi
> -bash: [[: .: syntax error: operand expected (error token is ".")
-eq is for numbers

== is for strings

See "man bash".

-Owen

On Thu, 28 Jul 2011, James B. Byrne wrote:
> I am trying to check for a single period '.' in a shell variable.
>
> $ I=.
> $ echo $I
> .
> $ if [[ "$I" -eq '.' ]]; then echo true; fi
   if [ "$I" = '.' ]; then ...

Use a single = rather than -eq (which tests numeric equality) and use
single brackets -- or, better, call test directly:

   if test "$I" = '.'; then ...

"help test" is your friend!

-- 
Paul Heinlein <> heinlein at madboa.com <> http://www.madboa.com/